From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: Re: GFS, what's remaining Date: Sun, 04 Sep 2005 09:37:15 +0100 Message-ID: <1125823035.23858.10.camel@localhost.localdomain> References: <20050901104620.GA22482@redhat.com> <20050903183241.1acca6c9.akpm@osdl.org> <20050904030640.GL8684@ca-server1.us.oracle.com> <200509040022.37102.phillips@istop.com> <20050903214653.1b8a8cb7.akpm@osdl.org> Reply-To: linux clustering Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Daniel Phillips , linux-cluster@redhat.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, ak@suse.de, Joel.Becker@oracle.com Return-path: To: Andrew Morton In-Reply-To: <20050903214653.1b8a8cb7.akpm@osdl.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-cluster-bounces@redhat.com Errors-To: linux-cluster-bounces@redhat.com List-Id: linux-fsdevel.vger.kernel.org On Sad, 2005-09-03 at 21:46 -0700, Andrew Morton wrote: > Actually I think it's rather sick. Taking O_NONBLOCK and making it a > lock-manager trylock because they're kinda-sorta-similar-sounding? Spare > me. O_NONBLOCK means "open this file in nonblocking mode", not "attempt to > acquire a clustered filesystem lock". Not even close. The semantics of O_NONBLOCK on many other devices are "trylock" semantics. OSS audio has those semantics for example, as do regular files in the presence of SYS5 mandatory locks. While the latter is "try lock , do operation and then drop lock" the drivers using O_NDELAY are very definitely providing trylock semantics. I am curious why a lock manager uses open to implement its locking semantics rather than using the locking API (POSIX locks etc) however. Alan